Utilization of Reclaimed Asphalt As An Effective Unbound Aggregate Base Course (Wet Mix Macadam) Material, A Case In India

Abstract

The study was focused on determining the materials property of recycled granular materials containing different percentages of recycled asphalt pavement (RAP) to use as an unbound aggregate base course (WMM) material. Laboratory tests and field implementation were carried out to determine the physical and mechanical properties of virgin aggregates and various aggregate-RAP blends at different percentages. The results were used to evaluate the strength of granular layer for pavement construction through proper compaction and control of RAP usage. The tests were also conducted to check the standards and requirements specified by the Ministry of Road Transport and Highways (MORT&H) using the procedures of the Indian Standard (IS).The sieve analysis test results showed that gradation of material RAP 1 and RAP 2 are better than the virgin aggregate gradation currently used. The sieve analysis of RAP 1 and RAP 2 are more similar, so the average of both taken as RAP. The Proctor tests have been conducted with RAP and VA with individually and different percentage. The laboratory MDD is being decreased as the RAP percentage increases. The laboratory CBR results showed that the blends with high content of virgin aggregate achieved high bearing capacities. The Low CBR values were achieved by neat RAP materials of 100% RAP and it’s more than 100%. The blends containing 100% VA resulted in higher CBR values. RAP materials implemented in field as an unbound aggregate base course material (WMM) for trial found satisfied and achieved the field compaction criteria. Beyond determining materials property, the study review and asses current material production and road maintenance activity to consider major economic and environmental benefits emanated from using the recycled materials instead of virgin aggregate productions. In this regard, the economic benefits by using RAPs resulted in 50% saving of virgin aggregate production costs annually. In addition to economic benefits, re-use of RAPs may reduce road construction wastes generated from road maintenance.